Regarding the wiring of the inner part of a frequency converter, particularly the wiring connecting a smoothing capacitor and an inverter part, it is known that the inductance has to be reduced to restrain the surge voltage of the inverter part and to protect a semiconductor device.
About this method for reducing the inductance, it is disclosed in Japanese Patent Application Publication No. JP-A-11-89247.
In the JP-A-11-89247, it is described that “It is characterized in that the wiring part (20) of a first, a second and a third DC voltages are constituted as a structure wherein a first, a second and a third planar conductors (201, 202, 203) and a first and a second insulating sheets (204, 205) are alternately laminated. By constituting the laminated structure like this interposing the planar conductors between the insulating sheets, the wiring inductance can be reduced also in an equipment which converts three or more DC voltages to an AC voltage.”